There was a period, the last seventy five years of the 19th century, when scientific experimentation based on the phenomenon of “the persistence of vision” in which the brain retains the impression of an object for a fraction of a second after its disappearance creating the possibility of apparent motion. These devices thrilled and delighted generations of people, and many are still with us today. Optical toys were the creation of scientists concerned with understanding the functioning of the eye and brain. There growing understanding of how an image is briefly retained by the brain(at the time they were doing their work they thought it was retained by the eye) led them to play with a combination of drawings, slits and mirrors to create the illusion of continuous movement.

Their experiments led to the production of a series of wondrous toys which were given names with Greek derivatives that ended with scope or trope-the Greek for viewer.

Dr. John Ayston Paris, a London physician started the parade of persistence of vision toys in 1825 with the Thaumatrope(turning wonder viewer). Two different parts of a drawing are painted on either side of a card. When the card is twirled with strings at two edges the images merge, creating one single image. The most famous thaumatrope is the bird in the cage. On one side a bird is painted, on the other a cage. When the viewer twirls the card and keeps looking the bird appears in the cage.

This incredible toy unleashed an efforts to see if a merging of images could lead to the more ambitious task of creating what would appear as uninterrupted motion. Armed with a growing theory of persistence of vision could many drawn images of a horse in slightly different poses, or a jack in the box drawn with different phases when combined with slotted discs, or presented in drums with slots, or later with mirrors appear for the viewer as uninterrupted motion?

Joseph Antoine Plateau, a dedicated scientist, who would lose his eyesight as a result of experiments with the effects of light on the retina (he stared at the sun for too long), devised the next important toy the Phenakistiscope (deceptive viewer) in 1832. Separately, the same year, Simon Stampfer independently developed a similar device called the Strobascope (whirling viewer).

Both devices worked similarly. First a progression of slightly differentiated drawing was made on a disc, than a similar number of slits were cut into the outside edge of the disc. When the disc was mounted on a handle and the viewer stood behind the disc, a moving picture could be created by spinning the wheel while watching the drawings in a mirror through the slots. The slots acted as a shutter and what appeared was single moving drawing.

Plateau’s and Stamfer’s toys represented a major scientific breakthrough in understanding persistence of vision and how to permit stationary imaged to be manipulated to create the illusion of motion. What followed was a wonderful series of toys based on this principle.

The Phenakistiscope, which was really a toy limited to use by one viewer, was soon joined by the Zoetrope. First described by William George Horner in 1834, and originally called the Daedaleum this device did not achieve its popularity until 1860s when it was patented in America as the Zoetrope (wheel of life) by William Lincoln. It utilized the same principles as the Phenakistiscope but now several people could watch what the toy did simultaneously. First images were drawn on a band. The band was then place inside a slotted cylinder with the same number of slots as drawings. Viewing the band through the slots in the turning cylinder again appeared to create motion. The Zoetrope had two advantages over the Phenakistiscope. First, you no longer had to retreat to a mirror, and second, more than one person at a time could watch the image.

The Zoetrope was improved upon or changed depending on your perspective, by the invention of the Praxinoscope by the Frenchman, Emile Reynaud in 1877. Reynaud also placed his images on a strip. However he eliminated the slots on the cylinder and put a set of mirrors facing the strip on the smaller cylinder inside the device, now when the Praxinoscope was twirled the viewer could see the motion in the mirrors. This helped overcome the distortions caused by the slots in the Zoetrope, and provided a brighter, clearer image, since there was no interruption of light. The Praxinoscope was made somewhat more elaborate by Reynaud with the invention of the Praxinoscope Theatre in 1879, which added a proscenium-framed viewing point,

Interest in persistence of vision spawned another series of inventive toys that were popular in the later part of the 19th century and the beginning of the 20th century, which largely utilized the wonders of photography. First were flick books, invented by Edward Linnert in 1860 wherein a series of drawings or photographs, each image slightly different from the other in a progression of movement, are flicked” by the thumb, allowing the viewer to see a little movie. The flick book concept was also utilized by the more mechanical Mutoscope (changing viewer) invented by the American, Herman Casler, in 1884. Images for the Mutoscope were taken by a special camera, the Mutagraph, which made a large number of photographs in a short frame of time. These images were then places on a large reel and using crank to turn the images and mechanical thumb for separation, large flick books were created. The Mutoscope took the flick book out of a person’s hands and into large halls, but the home use was again spawned with the development of Kinora, which was really a miniaturized Mutoscope.